An LTE (Long Term Evolution) mobile communication system is required to be operated while satisfying protection standards for adjacent frequency bands.
As shown in FIG. 6, the LTE specifications permit the system to reduce the maximum allowable transmission power of a mobile station UE when it is difficult to comply with the protection standards. In general, such an amount of reduction is called “A-MPR (Additional-Maximum Power Reduction).”
In a region where the “A-MPR” is applicable, a radio base station eNB is configured to notify of a method for applying the “A-MPR” by broadcasting a network signaling value called “NS (Network Signaling)” or “additionalSpectrumEmission” which is defined for a supported band.
In an example of FIG. 6, in a region A, a frequency band in which a system X is operated has a sufficient gap from a frequency band in which a system Y is operated. Accordingly, an interference level from the system X is attenuated to an allowable interference level in the system Y.
On the other hand, in a region B, sufficient attenuation of the interference level from the system X cannot be expected in the system Y. Hence, the radio base station eNB in the system X notifies the mobile station UE of the “A-MPR” by using the NS.